Comparison of Silver Impregnated and Conventional Spigots in Ceramic Water Filters Devices

Marlyn Mendoza*, Monica Krakue** and Vinka Oyanedel-Craver*

*Department of Civil and Environmental Engineering; **Department of Chemical Engineering


Ceramic filters water filtres (CWF) are a promising point-of-use water treatment technology in the developing world that can be made with local materials and labor.  Currently CWFs are manufactured by pressing and firing a mixture of clay and a combustible material such as flour, rice husks, or sawdust prior to treatment with AgNPs.  The filter is formed using a filter press, air-dried, and fired in a flat-top kiln, increasing the temperature gradually to about 900 ˚C during an 8-h period.  This forms the ceramic material and combusts the sawdust, flour, or rice husk in the filters, making it porous and permeable to water.  After firing, the filters are cooled and impregnated with a silver solution (either AgNPs or silver nitrate) by either painting with, or dipping in (Rayner, 2009).  After painting with the antibacterial solution the ceramic component is commonly placed in a five gallons bucket. The contaminated water is placed inside the ceramic component from where it percolated through the porous matrix of the ceramic removing pathogenic microorganism (Oyanedel-Craver, 2008; Bielefeldt et al., 2009). The clean water drip into the plastic bucket where is stored and can be accessed through the spigot located at the bottom of the plastic receptacle. The CWF are capable to remove between 3 to 4 log of the microbial load in the influent water, however is has been observed that re-growth can happen after several month of usage (Kallman et al., 2012). The spigot has been identified as a potential sources of re-contamination of the purified water (Cohen, 2011).

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